java - Server doesn't work with more than one connection -

i've got working simple client-server app. problem works fine 1 started client, not 2 or more. establish connection, when try enter text in first or second, server breakes. think problem may @ function broadcast() in server.java.

server.java

public class server {     final int port = 5000;     private arraylist<newclient> al = new arraylist<newclient>();     private scanner in;     private printwriter out;     private simpledateformat sdf;     private int uniqueid = 0;      private void go(){          try{             serversocket serversocket = new serversocket(port);             system.out.println("waiting clients...");              while(true) {                 socket s = serversocket.accept();                 newclient chat = new newclient(s);                 system.out.println("client number " + chat.getid() + " connected from: " + s.getlocaladdress().gethostname());                 al.add(chat);                 thread t = new thread(chat);                 t.start();              }         }catch (exception e) {             system.out.println("problem establishing network connection: ");             e.printstacktrace();         }      }      public static void main(string[] args) {         server server = new server();         server.go();     }      class newclient implements runnable{         private socket socket;         private int id;          public newclient(socket s) {             this.socket = s;             this.id = ++uniqueid;         }         public int getid() {             return this.id;         }          @override         public void run() {             try{                 in = new scanner(socket.getinputstream());                 out = new printwriter(socket.getoutputstream());                 sdf = new simpledateformat("hh:mm:ss");                  while(true) {                     string input = in.nextline();                     system.out.println("client said: " + input);                     broadcast(input);                 }             }catch (exception e) {                 e.printstacktrace();             }          }         private void writemsg(string input) {             string msg = input + " on " + sdf.format(new date());             out.println("you said: " + msg);             out.flush();         }          private void broadcast(string input) {             (int = 0; < al.size(); i++) {                 newclient t = al.get(i);                 t.writemsg(input);             }          }     }  } 

client.java:

public class client {     final int port = 5000;     final string host = "127.0.0.1";     private scanner stdin;     private scanner in;     private printwriter out;       private void go() {         setupnetwork();     }      private void setupnetwork(){         try{              socket s = new socket(host, port);             system.out.println("you connected " + host);             newclient client = new newclient(s);             thread t = new thread(client);             t.start();         } catch (exception e) {             system.out.println("problem connection server: " + e);         }     }     public static void main(string[] args) {         client client = new client();         client.go();     }      class newclient implements runnable {          private socket socket;         public newclient(socket s) {             this.socket = s;         }          @override         public void run() {             try {                 stdin = new scanner(system.in);                 in = new scanner(socket.getinputstream());                 out = new printwriter(socket.getoutputstream());                  while(true) {                     system.out.print("> ");                     string input = stdin.nextline();                     out.println(input);                     out.flush();                      if(in.hasnext()) {                         system.out.println(in.nextline());                     }                 }             }catch (exception e) {                 e.printstacktrace();             }         }     }  } 

when opens 2 client.java , connect server.java ok. when try send message 2 opened clients server returns these errors:

java.lang.indexoutofboundsexception: end      @ java.util.regex.matcher.region(matcher.java:1038)      @ java.util.scanner.findpatterninbuffer(scanner.java:1010) client said: sds     @ java.util.scanner.findwithinhorizon(scanner.java:1679)     @ java.util.scanner.nextline(scanner.java:1538)     @ server$newclient.run(server.java:66)     @ java.lang.thread.run(thread.java:745) 

what's happening code scans first line client ("sds", printed stdout), , loops , tries scan next line client. since client hasn't sent more yet, input stream scanner throws exception.